Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates generally to docking a laptop computer to a docking station. More particularly, the invention relates to powering the laptop through the docking station when the laptop is in the docked position. More particularly still, the invention relates to powering the laptop across a USB interface when in the docked position.
2. Background of the Invention
Computer systems come in many shapes, sizes and computational ability. For persons who work in designated locations, a standard desktop computer may be sufficient to fulfill that person""s needs. However, for a user who travels frequently and needs computing power in those travels, a portable or laptop computer is desirable.
Laptop computers are characterized in that the entire computing functionality is incorporated into a single package. That is, the motherboard, hard drive, disk drives, CD ROM drives, keyboard and display are all packaged in a compact device typically weighing less than ten pounds. Laptop computers are fully functional in that they may execute the very same programs, for example word processors and spreadsheet programs, as full sized or desktop computers. Laptop computers have a battery that allows for remote operation of the laptop even in locations where alternating current (AC) wall socket power is not available.
While laptop computers may address portable computing needs, they are not without their limitations. For example, the keyboards of most laptop computers are a non-standard size. That is, the keys may be slightly closer together and not as ergonomically placed as a standard keyboard. Further, standard keyboards typically have function keys, cursor control keys and a full numerical keypad. In laptop computers these keys are incorporated onto the standard keys by means of shift and function control. A further limitation of laptops, given the relatively small size, is they only have a limited number of communication ports available. That is, a laptop may support only a single parallel port, a single serial port and a single Universal Serial Bus (USB) port. Also, the display devices for laptop computers are typically small, as compared to desktop monitors, to keep the overall size of the laptop computer small.
Many laptop users address limitations of laptops by some form of docking station. When the user returns to the home or office, the laptop is xe2x80x9cdockedxe2x80x9d with a non-portable unit. Docking in this manner may expand the capabilities of the laptop computer to include a full size keyboard, a full size monitor, more serial ports, and other functionality typically associated only with desktop computing devices.
The docking station can take many forms. For example, the docking station may extend one of the expansion buses within the laptop computer, e.g. a peripheral components interconnect (PCI) bus, to the docking station such that full computing functionality may be housed within the docking station. Expanding the PCI bus gives the docking station the ability to include a hard drive, expansion cards and the like. For laptop computers that dock to this type of docking station, the docking station typically provides power to the laptop within the docking connector between the laptop and the docking station.
A second type of docking station, while extending the laptop""s capabilities, it is not as extensive as the dock station that extends one of the expansion buses of the laptop. This second type docking station is commonly referred to as a port replication docking station. By port replication it is meant that by plugging the laptop into the docking station, more serial and parallel ports are available for connection to printers, scanners, full size display devices, serial or parallel pointing devices and the like. As with the full docking station explained above, these port replication docks typically also include power connections in the docking connector.
Another method of expanding the capabilities of a laptop may be a form of port replication across a USB port. A user connects a laptop, via a USB connection, to a port replication device which generates plurality of communication ports for use as described above. However, in situations where port replication is accomplished across the USB connector, the laptop user also plugs the laptop into a separate source of power, or operates the laptop on battery power. Given that the user most likely intends to use the laptop for an extended period of time in the location where port replication is desirable, a user of the such a system plugs the AC/DC power converter (also known as a power xe2x80x9cbrickxe2x80x9d) into a standard AC wall socket on its input and its output into the laptop computer. Thus, in this situation the user is required to plug in at least the USB expansion connection as well as a power cable. Also, there are prior art devices that have the appearance of a full docking station, that is the laptop may physically couple to a non-portable docking station where the act of docking couples the USB ports; however, these devices still require the user to separately apply power to the laptop.
Thus, it would be desirable to have a USB based docking station that has the capability of both operating the laptop computer and charging the batteries in the laptop computer while docked without the need to plug in a separate power connection, thus reducing the time and complexity to couple the laptop to the docking unit. Despite the desirability of such systems, none are available in the prior art.
The problems noted above are solved in large part by a laptop computer and related docking station adapted to supply power from the docking station to the laptop computer across the USB connection. To accomplish this, the laptop computer is modified to have circuitry which is capable of being detected across USB power rails by the docking station and also capable of turning off the five volts typical supplied by the laptop onto the USB port, and instead, receiving power at 18.5 volts, from the docking station across the USB connections. The laptop computer may be operated by the dock unit supplied power and, if necessary, the laptop""s battery may be charged. Likewise, the docking station contains circuitry coupled to the power rails of the USB port which allows the docking station to detect whether the laptop computer coupled to the docking station is capable of receiving power.
Thus, a laptop user need only plug the laptop into the docking station via the USB port, even if the battery for the laptop computer is drained. Once physically coupled to the docking station, the docking station detects whether or not the attached laptop is capable of receiving power across the USB port. If so, the docking station ramps power to the laptop computer to facilitate its operation.